Using an old idea, the Shadow Grid technique, and applying it to a new tube design, an audio power pentode, a tube with very desirable characteristics was obtained. Following the introduction of the 6FG5 Shadow Grid pentode, a logical extension of the low screen current advantages of this construction was to incorporate it in a power pentode for audio applications. Characteristics and construction of an experimental pentode are given, with typical output and distortion figures. Featuring very low audio input drive voltages, this new design may permit, in many cases, a reduction in the number of stages of amplification required.
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